Components of a Hot Water BoilerThe boiler is more complex than a
forced air furnace in that it has more parts, valves and controls. However gas-fired boilers are fairly reliable and most problems, when they do occur, usually relate to the expansion tank or water circulator pump(s).
Let's take a quick look at the major components of the boiler for a forced-water (hydronic) system:
Hot Water Supply Side:
Aquastat - The thermostat that regulates the boiler's temperatureGas Valve and Burners - Combustion assembly that heats the water chamberCombination Pressure / Temperature Gauge (Tridicator) - Monitors water temperature and pressureWater Feed Valve - Controls water flow to boilerPressure Reducing Valve - Automatically maintains correct water pressure at about 12-15 psiAir Vent - Automatically purges unwanted air from hydronic systemExpansion Tank - Critical component that allows expansion of water as it heatsFlow Control Valve - Regulates flow of hot water to systemPressure Relief Valve - Relieves high water pressureHot Water Return Side:
Circulator - Electric pump that circulates water through the systemDrain Valve - Valve that opens to allow draining the boiler.
